Neon lighting devices are disclosed in U.S. Pat. No. 4,584,501(Cocks et al.), U.S. Pat. No. 4,990,826 (Cocks et al.), U.S. Pat. No. 5,036,243 (Cocks et al.). Generally, these patents disclose multifaceted lighting devices comprising glass or other vitreous plates which are hermetically sealed together to form a device with internal and enclosed channels. These enclosed and internal channels are thereafter evacuated and backfilled with an inert gas such as neon which is thereafter ionized through the provision of a series of electrodes.
Generally, the method for forming the glass component of these prior art neon lighting device involved cutting channels in a bottom glass plate followed by hermetically sealing, via the use of a glass frit, another glass top plate to this channeled glass bottom plate. Various methods were used to cut the channels into the bottom glass plate including grinding, etching and sand blasting through an adhesive rubberized mask exhibiting a pattern identical in shape to the desired channel pattern. The result of this cutting and subsequent fritting was that formation of the glass component of these lighting devices was an expensive and inefficient process and the resultant glass component was too heavy for use in those applications where weight was a concern, e.g., automotive applications.
Other more recent flat type lighting devices are disclosed in U.S. Pat. Nos. 5,041,762 (Hartai), 5,220,249 (Tsukada) and 5,223,262 (Lynn et al.). However, each of these references produces the glass body in generally the same manner; two glass plates fritted or sealed together. For example, Tsukada discloses a pair of transparent plates assembled and sealed together by a solder glass with a groove formed on the surface of one of the transparent glass plates thereby forming a discharge channel.
The principal objective of the present method is to provide for an improved method of forming the glass component for use in neon lighting devices; one which is simpler, more efficient and less costly than the prior art cutting or forming and fritting method, and which produces lightweight, sealant-free glass envelopes. In other words, the present method provides for a high volume, low cost method of producing lightweight glass articles possessing enclosed internal channels for use in light-emitting devices.